Self-destruction fuze for spin projectiles



April 18, 1967 F. lRlON SELF-DESTRUCTION FUZE FOR SPIN PROJECTILES Filed April 9, 1965 2 Sheets-Sheet 1 April 18, 1967 F. IRION SELF-DESTRUCTION FUZE FOR SPIN PROJECTILES Filed April 9, 1965 2 Sheets-Sheet 2 fl M QQ/M United States Patent 3,314,362 SELF-DESTRUCTION FUZE FOR SPIN PROJECTILES Ferdinand Irion, Ennetbaden, Aargau, Switzerland, assignor to Oerlikon-Buhrle Holding A.G., Zurich- Oerlikon, Switzerland Filed Apr. 9, 1965, Ser. No. 446,861 8 Claims. (Cl. 10271) The invention relates to -a self-destruction fuze for spin projectiles, whose rotary speed of self-destruction is automatically adjusted to a predetermined value depending on the maximum rotational speed of the projectile by a pivotable body under the action of the centrifugal force generated by the spin of the projectile in opposition to the resistance of an upsettable element, the resistance to deformation of which increases with the progressive deformation thereof.

In a known self-destructing fuze of this kind the adjust-able body is constructed as a nut, the screw thread of which is engaged by a screw bolt arranged in the axial direction of the fuze, and the circumference of which is engaged by centrifugal bodies, which are guided on a conical internal surface of the fuze casing, and which during the rotational acceleration of the projectile carrying the fuze in the barrel of the weapon ars displaced by centrifugal force in such a manner, that they shift the body axially while increasing the loading of a destruction spring forming a deformable support. Owing to the loading of said spring increasing upon axial displacement of the nut, a certain axial displacement results for any maximum rotational speed of the projectile. The rotational speed of the projectile decreases gradually after the same has reached its maximum rotational speed when leaving the barrel. During this decrease the nut is held in the aforesaid position with the aid of frictional resistance means, which have necessarily to be provided for this purpose in spite of the loading of the spring exceeding the likewise decreasing centrifugal force. These resistance means may be effective in the screw thread of the nut or'between the latter and the centrifugal bodies. Since these resistance means are active also during the axial displacement of the nut, this displacement is determined not only by the spring characteristic but also by the friction of these resistance means. This friction is, however, subject to great variations as between one fuze and another, e.g. owing to unavoidable differences in the surface condition in mass production. Consequently it is diflicult with the known self-destruction fuzes to attain an accurate dependence between the maximum rotational speed reached by the projectile and the axial displacement of the nut.

The present invention has the primary object of overcoming this disadvantage and of providing a self-destruction fuze wherein the dependence of the resistance offered to the displacement of the centrifugal body by the upsettable element can be readily adapted to actual requirements by selection of the shape and of the material of this body. It is another object of the invention to provide a fuze of the kind referred to the distance of the point of self-destruction of which from the muzzle of the gun is practically independent of the muzzle velocity and rotational speed of the projectile when leaving the muzzle, as well as of the temperature of the ammunition.

With these and other objects in view which will become apparent from this specification and accompanying drawings, I provide a self-destruction fuze for spin projectiles comprising in combination: a fuze body, a hood screwed to said fuze body, a bearing body mounted inside said fuze body and hood, an axle arranged perpendicular to the projectile axis in said bearing body, a centrifugal body pivotally mounted about said axis, a plastically upsettable element mounted in said bearing body opposing the angular deflection of said pivotally mounted centrifugal body in response to centrifugal force generated by the spin of said projectile, the rotational speed of the projectile at which self-destruction occurs being adjusted to a predetermined value depending on the maximum rotational speed of the projectile, and the resistance of said plastically upsettable element to deformation increasing with progressive deformation.

These and other features of my said invention will be clearly understood from the following description of some embodiments thereof given by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section of a first embodiment of a fuze in the transport position;

FIG. 2 is a cross-section on the line Il-II of FIG. 1;

PEG. 3 is an illustration analogous with FIG. 1, but in the condition immediately preceding self-destruction;

FIG. 4 is a longitudinal section of a second embodiment of a fuze in the transport condition;

FIG. 5 is a cross-section on the line VV of FIG. 4;

FIG. 6 is an illustration analogous with FIG. 4, but in the condition immediately preceding self-destruction;

FIG. 7 is a scrap section of FIG. 1, on a larger scale with a modification of the plastically upsettable element.

In the fuze illustrated in FIGS. 13 a bearing body 1 provided with a central bore 1a of stepped diameter is inserted in the fuze body 2. In this hearing body a sleeve 3 is inserted which is secured in its position by a hood 4, which is screwed to the fuze body 2 and bears on the end face of the sleeve 3. In a cavity formed by the fuze body 2 and thebearing body 1 a spherical rotor 5 is journailed, in whose bore 5a, which passes through its centre, the detonator capsule 6 is inserted. The bore 2a in the fuze body forms the connection between this cavity and a priming charge (not shown in the drawing) arranged behind it. The axis of the rotor bore 5a includes in the transport position of the fuze an angle with the longi-' tudinal axis thereof, the rear end face 7a of the hammer sleeve 7 abutting a milled face 5b of the rotor. The striker pin point 8 fixedly connected with the hammer sleeve 7 engages in a slot 50 cut from the milled face 5b in the direction of the axis of the rotor bore 5a. The hammer sleeve 7 is guided in a bore for of the bearing body and a bore 3a of the sleeve 3, and is subject to the bias of the destruction spring 9 arranged in its interior, whose loading is regulated by a movable bushing 10 extending into the hammer sleeve 7. In three radially directed bores spaced at equal angular intervals from one another of the hammer sleeve spherical centrifugal bodies 11 are mounted (see FIG. 2).

The ramp-shaped inclined approach face 30 connects the two bores of different diameter 3a and 3b of the sleeve 3 into which a slot 12 is cut from the front in a direction parallel to the axis of the fuze. The radially directed bore 13 arranged ahead of this slot is closed by a ring 14 pushed over the sleeve 3, which ring supports the deformable element 15 arranged in this bore, the end face of which is abutted by a presser bushing 16 movably guided in the bore 13. This element is made of a soft material,

for example of very pure aluminum. Owing to its conical shape this element can be upset in its axial direction by a force loading it in this direction, the upsetting increasing with increasing load. The resistance offered by the element 15 to a lever arm 18a is so dimensioned, that the moment transmitted to the lever 18- is a multiple of the moment derived from the spring 9. Owing to this excess force the lever arm 18, the upsettable element 15 and the bushing 16 may be laid out without regard to the strength of the destruction spring 9.

On an axle 17 directed transversely of the fuze axis, penetrating through the wall of the sleeve 3 and fixed to the cap 4 a fiat body 18 is pivotally mounted, which forms an L-shaped lever engaging with its longer rearwardly extending arm 18a in a slot 70 of the hammer sleeve 7 and the slot 12 of the sleeve 3, and contacting near its pivot axis the end face of the presser bushing 16. The other arm 18b which is nearly perpendicular to the first arm reaches through the slot 19a of a striker sleeve 19, abutting the hammer sleeve 7, into the interior thereof and bears on the forwardly belled end face of the bushing 10. Equilibrium of the lever 18 is established in the transport position of the fuze by the fact that the arm 18b loaded by the destruction spring 9 abuts a movable sleeve 20 arranged in the bore 4a of the hood 4. Between said sleeve 20 and a likewise sleeve-shaped inertia mass 22 abutting the bottom of the bore 4a of the hood 4 a safety element 21 is inserted, whose effect can be abolished by upsetting the same, whose resistance to deformation is a multiple of the initial tension of the destruction spring 9.

The striker sleeve 19 is guided slidably in a central bore 41) of the hood 4 extending to the tip thereof, and carries at its forward end a pin 23, on which bears a terminal sleeve 24. The end face of this sleeve 24 abuts a disc 25, which is movably inserted in the hood 4 and is contacted by a pill 26 consisting of a material fuzable at a low temperature and held by a cap 27 screwed to the hood 4.

The functioning of the fuze follows from its construction described hereinabove (see FIG. 3):

When firing the projectile fitted with the fuze, the inertia mass 22 is thrown rearward, whereby it plastically deforms i.e. shortens the safety element 21, so that the lever 18 is released thereby, and the sleeve 20 can move until its end face abuts the bottom of the bore 4a of the hood. Since the rotational speed of the projectile increases while passing through the barrel the lever arm 18a is subject to a centrifugal force proportional to the square of the rotational speed and increasing with the increase of the distance of its centre of gravity from the fuze axis, until this centrifugal force eventually grows so high, that this lever arm moves outward overcoming the resistance to deformation of the upsettable element 15, whereby at the same time the preloaded destruction spring 9 is loaded even more strongly by the movement of the other lever arm 18b.

The element 15 continues being plastically upset by the centrifugal force gradually increasing in the gun barrel, and the loading of the spring 9 is thus increased until the forces acting on the lever 18 have reached a new equilibrium, which is established atmaximum rotational speed, i.e. when the projectile leaves the muzzle. After the projectile has left the barrel, the fuzable pill 26 is heated by the heat of the dynamic pressure building up at the tip of the fuze to such an extent that it fuzes at a certain distance from the muzzle, whereby the detonator safety of the rotor is abolished and the latter can erect itself under the effect of centrifugal force until its axis coincides with the longitudinal axis of the fuze. When erecting itself, the rotor lightly raises the hammer sleeve 7 resting on its face 512 together with the striker sleeve 19, whereafter the hammer sleeve is again pushed back under the bias of the destruction spring 9, until the centrifugal bodies 11, which are likewise subject to centrifugal force and consequently contact the bore 3a of the sleeve, run on the ramp-shaped approach surface 30.

Thereby the hammer sleeve 7 is secured with the striker point 8 being new aligned co-axially with the bore 5a of the erected rotor, i.e. lying in front of the detonator capsule 6.

On its trajectory the rotational speed of the projectile gradually decreases owing to air friction, while the destruction spring 9 is kept loaded by the lever 18, which rests in its end position reached at the muzzle owing to the said excess force. The detonator safety of the hammer sleeve 7 is maintained until the component force parallel to the fuze axis of the supporting force transmitted by the approach surface 30 generated by the centrifugal force acting on the centrifugal bodies 11 exceeds the force of the destruction spring 9. When this is no longer the case, the centrifugal bodies 11 slide off the surface 30, being directed inward in the bores 7b of the hammer sleeve by the inclination of this surface 30. The hammer sleeve 7 with the striker pin 8 is thereby thrown rearward towards the detonator capsule 6 in the rotor and ignites the same, whereby the detonation of the explosive charge, i.e. the destruction of the projectile is effected.

When the projectile hits a target before self-destruction takes place, the column resting on the hammer sleeve 7 and consisting of the terminal sleeve 24, the pin 23 and the striker sleeve 19 is thrown rearward by the pressure acting on it from the front so as to overcome the resistance of the supporting centrifugal bodies 11, whereby detonation of the projectile is effected in the same manner as upon self-destruction.

The magnitude of the necessary loading of the destruction spring 9 depends on the rotational speeds arising on the trajectories of projectiles fired at different muzzle velocities, including the maximum and minimum thereof, and on different muzzle-leaving rotational speeds as a function of the distance measured on the trajectory from the gun. The regulator device, which adjusts the spring forces by the action of the centrifugal forces acting on the lever 18 at the muzzle, must be constructed accordingly. This is achieved primarily by suitably shaping the mutual contact faces between the lever 18' and the bushings 10 and 16, i.e. by the lever arms 18a and 18b varying their effective length on movement of the lever 13, and moreover by selection of a suitable resistance to deformation of the plastically upsettable element 15 depending on the angular deflection of the lever 18, i.e. by suitably shaping this element. The upsettable element 15 need not be conical as shown in FIG. 1, but can have any other suitable shape meeting the requirements, for example the form of a hollow cylinder 47 shown in FIG. 7, whose axis is arranged in the direction of the bore 13. When loaded by the bushing 16 or the lever 18, respectively, this cylinder is upset barrel-shape, whereby, as in the case of the conical deformable element 15 moreover with increasing deformation an internal strengthening of the very pure aluminium takes place which increases resistance to deformation.

In the second embodiment some components which are identical with the aforesaid embodiment are denoted by the same designations as there.

The fuze body 36* contains the rotor 5 in the cavity defined by it and by the bearing body 31. On this fuze body 30 a ring 32 is mounted, which is secured by the hood 33 screwed to the fuze body 30 and abutting its end face, and whose rear portion is provided with longitudinal slots 32a. Two semi-annular projections 35 jutting out forward from the fuze body 30 bound a slot 35a (see FIG. 5), whose middle plane coincides with that of the slot 32a machined in the ring 32 from the rear end face thereof. Two axles 36 arranged parallel to one another transversely of the fuze axis pass through the walls of these projections and are journalled in the ring 32, arresting the latter in its position, and serve for the pivotal mounting of two centrifugal levers 37 engaging in the slots 32a and 35a. These centrifugal levers are secured in their rest position by pins 39 engaging in grooves 370 cut into the rearward pointing lever arms 37a,

these pins 39 being guided in bores 30:: of the fuze body 30 and resting on safety elements 38 capable of being shortened by upsetting.

The outside of each of these levers 37 is contacted by a presser bushing 16 guided in a bore of the wall of the ring 32, which-as in the first embodiment-abuts a plastically upsettable element 15 inserted in the wall of the ring. The short arms 37b pointing forward of the lever 37 are provided with cam faces 37d inclined rearward towards the fuze axis and contacted by centrifugal bodies 40 in such a manner, that they practically exert no torque moment on the levers 37. These centrifugal bodies are formed by rollers 40 j-ournalled on axles 42 fixed in links 41, which links are pivotally attached to an axle 43 fixed to the striker pin 44. This striker pin 44, which in the manner explained with reference to the first embodiment rests in the transport position on the rotor 5, reaches through a central bore 33a of the hood 33 into the tip thereof, where its end face abuts the disc 25, which is arranged behind the fuzable pill 26 held by the cap 27. The destruction spring 45 abuts in front the bottom of the bore 33b of the hood, and at the rear abuts the guide bushing 46, which is slidable in said bore and rests on the collar 44a of the striker pin 44.

The manner of functioning of this fuze is largely identical with that of the fuze described with reference to the first embodiment; however, the device for regulating the self-destruction operates, in accordance with its construction, as follows:

When firing, the pins 39 moving rearward against the resistance of the deformable safety elements 38, release the centrifugal levers 37, whose arms 37a shorten the upsettable element 15 by plastically deforming the same, when the centrifugal force increases with increasing rotational speed of the projectile running through the barrel. At the same time these-arms can move outward at an increasing rate owing to the upsetting of the ele-v ment 15. Like in the first embodiment, a hollow cylinder 47 (according to FIG. 7), for example, may here be used instead of the conical upsettable element 15. The deformation attained at the highest number of revolutions determines the magnitude of the angular defiection of the centrifugal levers 37, and accordingly also the inclination of the cam surface 37d for the centrifugal bodies 40 subject to the action of centrifugal bodies 40 subject to the action of centrifugal force, which inclination has a constant angle up to self-destruction.

Accordingly, at comparatively high rotational speeds when leaving the muzzle a smaller angle of inclination of the cam surface 37d relative to the fuze axis, measured in the space ahead of its apex, is adjusted than at lower speeds, the preloading of the destruction spring 45 remaining constant in this second embodiment. For example the comparatively small angle of inclination of the cam surface 37d resulting from a high rotational speed when leaving the muzzle has the consequence that the centrrfugal force acting on the centrifugal bodies 40 can no longer prevent the slipping off of the centrifugal bodies under the bias of the destruction spring 45 and accordingly the destruction of the projectile even at a comparatively high rotational speed of the projectile, wh le, in contrast, owing to a low rotational speed when leaving the muzzle, the angle of inclination of the cams 37a is greater and the destruction of the projectile takesplace at an even lower rotational speed. The effect 1s accordingly analogous to that of the first embod1ment. Thereby the desired equalisation of the distances measured from the gun at unequal rotational speeds when leaving the muzzle is attained.

While I have described herein and illustrated in the accompanying drawings what may be considered typ cal and particularly useful embodiments of my sa d invention I wish it to be understood that I do not WlSh to limit myself to the particular details and dimensions described and illustrated; for obvious modifications will occur to a person skilled in the art.

What I claim as my invention and desire to secure by Letters Patent, is:

1. A self-destruction fuze for spin projectiles comprising in combination: a fuze body, a hood screwed to said fuze body, a bearing body mounted inside said fuze body and hood, an axle arranged in said bearing body perpendicular to the projectile axis, a centrifugal body pivotally mounted about said axle, a plastically upsettable element mounted in said bearing body opposing the angular deflection of said pivotally mounted centrifugal body in response to centrifugal force generated by the spin of said projectile, the rotational speed of the projectile at which self-destruction occurs being adjusted to a predetermined value depending on the maximum rotational speed of the projectile, and the resistance of said plastically upsettable element to deformation increasing with progressive deformation thereof.

2. A self-destruction fuze as claimed in claim 1, wherein said plastically upsettable element is arranged between said axle on which said centrifugal body is pivotally mounted and the free end of said body.

3. A self-destruction fuze as claimed in claim 2, comprising a destruction spring operatively connected with said centrifugal body in the sense of having its loading increased by the deflection of said body under centrifugal force, said centrifugal body being constructed as an L- shaped lever having one arm juxtaposed to said plastically upsettable'element and another arm biased by said destruction spring.

4. A self-destruction fuze as claimed in claim 2, comprising centrifugal masses, cam faces provided on said pivotally mounted centrifugal body being contacted by said centrifugal masses, the angle included by said cam faces with the projectile axis being reduced by the defiection of said pivotally mounted body under centrifugal force.

5. A self-destruction fuze for spin projectiles comprising in combination: a fuze body, a hood screwed to said fuze body, a bearing body mounted inside said fuze body and hood, an axle arranged in said bearing body perpendicular to the projectile axis, a centrifugal 'body pivotally mounted about said axle, a plastically upsettable element arranged opposite said pivotally mounted centrifugal body so as to be upset by angular deflection of the latter about its axle in response to centrifugal force generated by the spin of said projectile, the rotational speed of the projectile at which self-destruction occurs being adjusted to a predetermined value depending on the maximum rotational speed of the projectile, and the resistance of said plastically upsettable element to being deformed increasing with progressing deformation thereof.

6. A self-destruction fuze as claimed in claim 5, Wherein said plastically upsettable element is made of very pure aluminum.

7. A self-destruction fuze as claimed in claim 5, wherein said plastically upsettable element is a hollow cylinder having an axis disposed radially of the projectile axis.

8. A self-destruction fuze for spin projectiles compris ing in combination: a fuze body, a hood screwed to said fuze body, a bearing body mounted inside said fuze body 7 and hood, an axle arranged in said bearing body, perpendicular to the projectile axis, a two armed lever pivotally mounted about said axle, a plastically upsettable element arranged opposite said two-armed lever so as to be deformed by the angular deflection thereof about its axle in response to centrifugal force generated by the spin of the projectile, a locking device arranged within said fuze body and hood retaining said two-armed lever in a transport position and releasing the same in response to acceleration upon firing said projectile, the rotational speed of the projectile at which self-destruction occurs being adjusted to a predetermined value depending on the maximum rotational speed of the projectile, and the resistance 7 8 of said plastically upsettable element to deformation in- FOREIGN PATENTS creasing with progressive deformation thereof. 257,33 5 8/1926 Great Britain References Cited by the Examiner UNITED STATES PATENTS BENJAMIN A. BORCHELT, Examiner.

2,375,522 5/1945 Campbell 102-8 G. H. GLANZMAN, Assistant Examiner.

SAMUEL FEINBERG, Primary Examiner. 

1. A SELF-DESTRUCTION FUZE FOR SPIN PROJECTILES COMPRISING IN COMBINATION: A FUZE BODY, A HOOD SCREWED TO SAID FUZE BODY, A BEARING BODY MOUNTED INSIDE SAID FUZE BODY AND HOOD, AN AXLE ARRANGED IN SAID BEARING BODY PERPENDICULAR TO THE PROJECTILE AXIS, A CENTRIFUGAL BODY PIVOTALLY MOUNTED ABOUT SAID AXLE, A PLASTICALLY UPSETTABLE ELEMENT MOUNTED IN SAID BEARING BODY OPPOSING THE ANGULAR DEFLECTION OF SAID PIVOTALLY MOUNTED CENTRIFUGAL BODY IN RESPONSE TO CENTRIFUGAL FORCE GENERATED BY THE SPIN OF 